Lesson 5-5: Radicals
After this lesson, TSWBAT
 Simplify simple radicals by hand and by
calculator
Square Roots
To understand square roots, you must first understand where they come from.
3 squared is 9, so a
square root of 9 is 3
A square root of a number is ...
... a value that can be multiplied by itself
to give the original number.
... 3, because when 3 is multiplied by
itself you get 9.
A square root of 9 is ...
What can I multiply by itself to get this?
It is like asking:
So, let’s take a look:
Example 1
√𝟗 =
Your Turn!
Find the square root of the following numbers. Complete them like the one shown.
25
196
484
24025
1
Square Roots With Letters (Oh my!)
Finding square roots with letters works the same way
as finding square roots with numbers. Use the same
process. Let’s do one together:
Example 2
Your Turn
Find the square root of the following numbers. Complete them like the one shown.
Roots Other Than Square Roots
Finding roots other than square roots works the same way
as finding square roots. Use the same process. Let’s do
two together:
Example 3
Example 4
“cubed roots”
2
Your Turn!
Match the roots to their equivalent answers.
______1.
a.
12
______2.
b.
m4n2
______3.
c.
-12m4n3
______4.
d.
3x5
______5.
e.
2
______6.
f.
8x3
Practice
3
Finding Roots With A Calculator
Some radicals have roots that aren’t whole numbers. When that’s the case, a calculator must be
used to approximate an answer.
Example 5
Example 6
Example 7
Practice
4
More Practice
5